Extraction process



Oct. 6, 193,1. R. DE M. TAvEAu L f Y 1,825,762

EXTRACTION PROCESS 'Filed May l5' 1925 Err/aufruf? nveutoz Y my@ jan/em Patented Oct. 6, 1931 VUNrrlazD STATES PATENT OFFICE BENE DE M. TAVEAU, OF ELIZAEETH, NEW JERSEY, ASSIGNOB, BY MESNE ASSIGN- MENTS, T0 THE TEXAS COMPANY, OF NEW YORK, N. Y., A CORPORATION 0F DELA- 'WARE E XTRACTION PROCESS Application med May 15,

tions of oil are thus destroyed while the resultant acid sludge containing the main part of the impurities is practically Worthless or at the most of little value. Furthermorethe treatment of oil in such a manner involves complicated chemical processes and such treatment, therefore; requires careful technical supervision to insure a product acceptable to the user.

I have found, however, that this method y may be improved upon by extracting the unrefined material with a solvent to produce pure oil and a residue containing the impurities. ,This residue may be employed as fuel oil or for other suitable purposes after the extraction of the desired oilv to any extent considered practicable. The solvent utilized should be volatile so that it may' be vaporized from the extracted oil and be re-V circulated in the process. By the use of a closed system the loss of solvent is exceedingly small and costs are low.

The success of such a process depends to a large extent upon the oil to be refined and the solvent selected. I have found while working with lubricating oils that isopropyl alcohol is a suitable solvent for the pure oil while asphaltic and other impurities remain undissolved therein. The alcohol has a speciic gravity less than that of lubricating oil and consequently'may be introduced into the bottom of the body of oil to percolate up through it, extracting a portion during its passage.y Solvents having a speciic gravity greater than the material being extracted may also be used but in such case provision must be made for introducing the solvent 'at the 1925. Serial No. 30,430.

top and withdrawing it from the bottom of the vessel.

An additional advantage to be derived from my invention resides in its application to the refining of heavy asphaltic base residuum and the like, as for example, the material commonly known as flux oil. It has been found that such residuum may easily be treated in accordance with my process for the recovery of valuable lubricating oils therefrom, while by the methods usually practiced such recovery would be entirely impractical because ofthe excessive amounts of chemicals required to properly purify the oil and the comparatively small amount of refined material ultimately received.

For a better understanding of my invention reference may be had to the accompanying drawings in which Figure 1 is a diagrammatic showing of a plant apparatus for carrying out my process, while Figure 2 is a partially sectional View of laboratory apparatus. Figure 3 is an cnlar ed view of the top portion of the extraction vessel of Figure 2. Figure 4 is a sectional view of an inner extraction vessel for the apparatus shown in Figure 2 and to be employed when extracting with a solvent heavier than the oil.

In Fig. 1, 1 is the extraction vessel which may be of the usual agitator type employed for acid treatment of oils and is provided with coils 2 by means of which the temperature of the material to be extracted may be maintained within thedesired range by the circulation of steam or water. The extractor 1 is also provided with an inlet pipe 3 for admitting oil or other material to be extracted and wlth an outlet pipe 4 for the Withdrawal of the extracted residue. Pipe 5 leads the solvent into the bottom of the extractor 1 from the solvent stills 6 and 7 An overiow pipe 8 allows solvent containing extracted materia-l to pass into the settling chamber 9 which is also maintained at the same temperature as 4the extractor 1 by means of the heating or cooling coils 10. A pipe 11 siphons solvent from the chamber 9 when the solvent reaches the proper level therein and permits the solvent to low t0 still 7 through the valve 12 or to still 6 through the valve 13. The stills 6 and 7 are provided with drawo pipes 14 and 15, respectively, having suitable control valves therein and lead to the pipe 16, whereby the residual extract in either of the stills may be drawn pif to a suitable container. The risers 17 and 18 lead from the stills 6 and 7 to pipe 5 and haveI valves 19 and 20 for controllingthe fiow of solvent vapors. A

steam line 21 leads to a distributor 22 near the bottom of the exeractor 1 for the introduction of livesteam into the extracted residue to volatilize therefrom any solvent which it may retain at the end of the extraction, the uncondensed steam and solvent vapors passing out through the valve 23 and into the condenser 24 to be recovered.

To operate the process with this apparatus the extractor 1 is filled vwith crude petroleum residuum or other material to be extracted, to a point below the overflow pipe 8. Solvent from one of the stills. as for instance 6. is vaporized and is led through pipe to the bottom of the extractor 1. The solvent, having been condensed in its passage through pipe 5, enters the oil, gradually Hows up through the same and passes out through pipe 8 when sufficient solvent has collected to rise to that level in the extractor 1. The chamber 9 then becomes filled with solvent containing extracted pure oil and overflows through pipe 11 and since distillation is being carried on in still 6 the solvent is allowed to collect in still 7 by opening the valve 12 and maintaining the valve 13 in closed position- When practically all ofthe solvent in still 6 has been-vaporized heatingr thereof is discontinued and distillation is begun in still To accomplish this, valve is opened while valve 19 is closed. allowing the vapors from still 7 to enter the extractor through pipe 5. while the valve 12 is closed and the valve 13 opened to permit accumulation of the extracted material and solvent in the still 6. This operation is continued until substantially all of the volatile solvent is vaporized from the extracted oil in still 7. at which point the oil mav be drawn from still 7 bv opening the valve in the pipe 15. Distillation then is carried on from still 6 as before. As the removal of extracted oil reduces the volume of the unrefined oil in extractor 1. additional unrefined oil may be introduced through pipe 3 or the introduction of that material mavcontinuously take place during the extraction bv the proper adiustment of the valve in pipe'3.

After substantiallv all ofthe extractable oil has been obtained from the material in extractor 1. circulation of the solvent may be discontinued temporarily' While steam is introduced i nto the bodv of resid ne through the pipe 21 and distributor 22. The valve 23 should be opened to permit the escape of uncondensed steam and the solvent vaporized thereby to be condensed in the condenser 24. The residue in extractor 1 may then be drawn 'off by opening the valve in pipe 4 to fiow to suitable storage for use as fuel oil or for other purposes and another charge of unreined oil introduced into the extractor 1.

In Fig. 2, the extractor consists of an outer jacket 30, an inner extraction vessel 31 in which the material to be extracted is maintained an a cylindrical partition 32 serving the double purpose of providing a collection chamber 33 for the solvent overfiowing from vessel 31 as well as a chamber 34 for the circulation of cooling or heating fluid around the extraction vessel 31. The latter is provided with a gallery or settling chamber 35 at the top thereof to permit particles of material being extracted to settle out and be returned to the main body of material. A pipe 36 leads the solvent containing extracted material from the chamber 33 to the still 37 which may be heated in any suitable manner as by a steam bath or a Bunsen burner. Pipe 38 leads the solvent vapors generated in the still 37 to the condenser 39, an extension 40 of which introduces the condensed solvent into the bottom of the extraction vessel'31.

Pipe 38 is preferably jacketed alon its vertical portion to prevent undue con ensation of the solvent. In case it is desired to operate the extraction process at or near the boiling point of the solvent employed the apparatus may be provided with a condenser 41 connected to chamber 33 and extraction vessel 31 to condense and return to chamber 33 any solvent which may be vaporized therefrom.

The laboratory apparatus just described operates in substantially the same manner as the lant apparatus shown in Figure 1, the extra ted material collecting in still 37 together with solvent overflowing from the extraction vessel 31. It will be observed that provision has been made for carrying out the. extraction operation at any desired temperature up to the boiling point of the solvent but entirely independent of that factor. This permits taking advantage of the relative solubilities of the components of the refined oil in the solvent employed, by arranging the temperature of extraction to conform to the temperature of greatest relative solubility of pure oil and greatest relative insolubility of iin-- purities in the solvent. By utilizing this principle the extraction may be accomplished under the most favorable temperatures which are to be determined in each case by the particular solvent employed and the particularmaterial being extracted.

When extracting the oil with a solvent having a specific gravity greater than that of the oil under the conditions of extraction, it is desirable to substitute the extraction vessel 42, shown in Figure 4, for the extraction vessel 31 indicated in Figure 2. rl'he extension 4() ofthe condenser 39 may be disconnected when using the extraction vessel 42 so that the condensed solvent will drop from the end of the condenser 39 into the top of the extraction vessel 42 and the solvent, being heavier than the oil to be extracted, percolates down through the oil extracting a portion during its passage and collects at the bottom of the extraction vessel whence it will rise in the overow tube 43 and pass into the collection chamber 33. The solvent containing extracted material will then flow from chamber 33 to still 37 through pipe 36 as previously described.

- The apparatus shown and described is especially adapted for extracting hydrocarbon oils. 1t may, of course, be used for extracting other liquids or solid substances where it is desired to control the temperatures of extraction. While I have thus specifically described my invention the specic examples chosen to illustrate the same are not to be construed as limiting the invention, the principles of which are set forth in the appended claim.

What l claim is:

A process for the recovery of valuable lubricating oil from an asphaltbase residuum which comprises treating the residuum with isopropyl alcohol, separating the oil-alcohol solution from the undissolved asphaltic'matter, and evaporating the isopropyl alcohol to recover the lubricating oil.

In witness whereof I have hereunto set my hand this 12th day of May, 1925.

RENEW M. TAVEAU. 

